SAS
Member
When we moved into this house there was a non working Honeywell HE300 humidifier attached to a Trane XV80 furnace. The humidifier was disconnected, and when I connected it I discovered that the solenoid valve would no longer open. I replaced the solenoid valve, but the humidifier runs whenever the humidistat calls for it, whether the furnace is running or not. Since the humidistat connects directly to the humidifier, I figured the problem must be a relay providing power to the humidistat. Opening the cabinet to the furnace, there is indeed a current sensing relay, Research Products Model 50, installed there. Do these just fail? If so, would I be better off using a terminal on the furnace to control the humidifier, assuming I can figure out which one? Or should I just spend $30 or so and replace the relay?